First of all, it is important to keep communication and understanding. Communicate frankly with your partner and try to understand the reasons for their mood swings and the emotional needs behind them. Listen to and respect each other's feelings and express your support and concern.
Second, provide support and a sense of security. Emotional unstable partners may need extra support and security, so give them emotional support and understanding as much as possible. Express your support and concern, help them deal with their emotions, and provide necessary support and help.
At the same time, I suggest that you and your partner explore appropriate emotional management strategies. This may include seeking professional help, such as psychological counseling or therapy, to learn to deal with emotions more effectively. Help them develop healthy coping mechanisms and self-regulation skills, such as deep breathing, meditation and exercise.
The most important thing is to pay attention to your mental health and boundaries. An emotionally unstable partner may have an impact on your emotional and psychological state, so make sure you also have your own support network and coping mechanism. Seeking professional help, such as psychological counselors, can provide more guidance and support.
Finally, each relationship is unique and needs to be dealt with according to the specific situation and personal needs. If your emotionally unstable partner has seriously affected your happiness and health, or you feel that you can't handle this relationship well, you can consider seeking professional help and advice to help you make an appropriate decision.